2026 ICD-10-CM Diagnosis Code O40.9XX1Polyhydramnios, unspecified trimester, fetus 1
O40.9XX1 is a billable ICD-10-CM diagnosis code for polyhydramnios, unspecified trimester, fetus 1. The 7th character 1 identifies fetus 1 in a multiple gestation pregnancy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Polyhydramnios and other problems of amniotic cavity.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O40.9XX1.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Health Problems in Pregnancy
A health problem in pregnancy is any disease or condition that could affect your health or the health of your fetus. Some health problems may make it more likely that you will have a high-risk pregnancy. A high-risk pregnancy is one in which you, your fetus, or both are at higher risk for health problems than in a typical pregnancy.
The full article covers:
- What are health problems in pregnancy?
- What raises my risk for health problems during pregnancy?
- Can chronic health conditions cause problems in pregnancy?
- Can health problems in pregnancy be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O40.9XX1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About O40.9XX1Overview
Is O40.9XX1 (Polyhydramnios, unspecified trimester) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report polyhydramnios, unspecified trimester, fetus 1 on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character 1 in O40.9XX1 mean?
The final character 1 identifies the fetus in a multiple gestation pregnancy: this code reports polyhydramnios, unspecified trimester for fetus 1.
What MS-DRG does O40.9XX1 group to?
When polyhydramnios, unspecified trimester, fetus 1 is the principal diagnosis on an inpatient stay, it groups to MS-DRG 817, 818, 819, 831, 832, 833, with relative weights from 0.5229 to 1.6880 depending on complications. Higher weights mean higher Medicare reimbursement.
Who can O40.9XX1 be reported for?
The Medicare Code Editor checks polyhydramnios, unspecified trimester, fetus 1 against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
What is the ICD-9 equivalent of O40.9XX1?
Under the General Equivalence Mappings, polyhydramnios, unspecified trimester, fetus 1 converts to ICD-9-CM 657.00 (polyhydramnios-unspec). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
